1. Field of the Invention
The present invention relates to link chains and, more particularly, to the pins by which adjacent links of a chain are pivotally coupled together.
2. Description of the Prior Art
In the usual chain, each link is pivotally connected at pivot joints in end to end array with adjacent links by means of pins which extend through aligned openings in the links. It is generally necessary to lock the pin into the links to prevent displacement therefrom which would result in a separation of the chain.
One method used heretofore to lock the pins in the links consists of upsetting their ends as shown, for example, in U.S. Pat. No. 3,107,777, which issued to Steorts Oct. 22, 1963. Such a riveted pin, however, cannot be removed without destruction, and separation and reconnection of the chain for repair or replacement of links is difficult and uneconomical.
Another previously used method to secure the pins in the chains consists of inserting cotter pins in transverse bores through the ends of the pins, as shown in U.S. Pat. No. 3,180,165, which issued to Bain on Apr. 27, 1965. Another prior art method of retaining the pins in the chain is by the use of spring clips on the ends of the pins, as shown, for example, in the U.S. Pat. No. 3,353,421 to Ketterle, which issued Nov. 21, 1967. Cotter pins and spring clips can become dislodged during operation of the chain, and constitute small parts which, particularly in field installation or repair of a chain, can become lost or misplaced.